We use some really great tools for our development process.


Programming:


Unity 3D (v3 and v4)
   Free GUI based tool for making games. Built in pathfinding, animation, and easy to use scripting make this a great tool for game development.



File Sharing and Team Work:


Dropbox
    External file storage you can install to your PC, and when dropping files in, syncs between all PCs.

.git repository
    This is a great tool for any development team. Automatically update and push new additions between ALL parts of your program or project, and revert back if you need to.